1. Field of the Invention
Embodiments of the invention generally relate to vacuum pumping systems.
2. Background of the Related Art
Semiconductor wafer processing is generally performed in process chambers having sub-atmospheric pressures. Vacuum pumping systems are commonly utilized to achieve and maintain sub-atmospheric pressures within the processing chambers and are typically remotely located (i.e., outside the clean room) to prevent adverse affects on substrate processing. These vacuum pumping systems typically have a large footprint, creating noise in excess of 60 dB, and generate vibrations that can exceed 3.0 m/s2. Vacuum pumping systems serving a typical process chamber generally have a pumping capacity in the range of about 1600 l/min in order to satisfy the needs of typical substrate processing operations. Vacuum pumping systems of this capacity generally consume up to about 4 kilowatts-hour of electricity.
New vacuum pumping systems, such as the iPUP(trademark) vacuum pump developed by Applied Materials, Inc. of Santa Clara, Calif., and described in U.S. patent application Ser. No. 09/220,153, filed Dec. 23, 1998, and U.S. patent application Ser. No. 09/505,580, filed Feb. 16, 2000, which are hereby incorporated by reference in their entireties, generally describe a novel integrated pumping system that consumes approximately half the amount of energy required by conventional vacuum pumping systems of equivalent capacity. However, the power consumption of these vacuum pumping systems remains quite large. Reducing the power consumption is desirable both for reducing the energy associated with maintaining vacuum pressures and for reducing the heat generated and subsequent cooling requirements of the vacuum system, the clean room and the facility. Additionally, conservation of energy is additionally desirable for social, economic and environmental benefits.
Therefore, there is a need for a vacuum pumping system that reduces energy consumption.
Generally, a vacuum pumping system having efficient power usage is provided. In one embodiment, the vacuum pumping system includes a first pump, a check valve and a second pump. The check valve and second pump are coupled in parallel to an exhaust line of the first pump. The first pump and second pump have a ratio of internal volume that is about 20 to about 130.
In another embodiment, the vacuum pumping system includes a first pump, a check valve and a second pump. The check valve and second pump are coupled in parallel to an exhaust line of the first pump. The first pump and second pump have a ratio of power consumption that is about 5 to about 20.
In yet another embodiment, the vacuum pumping system includes a first pump, a check valve and a second pump. The check valve and second pump are coupled in parallel to an exhaust line of the first pump. The first pump and second pump have a ratio of pumping capacity that is about 50 to about 200.